(1) Field of the Invention
The present invention relates to a copier which has an automatic document feeder laid over the top of the original table thereof in an openable and closable manner and can selectively implement either the manual copy mode in which the image of an original manually set on the original table is copied or the automatic copy mode in which the images of originals automatically fed by the automatic document feeder are copied.
(2) Description of the Related Art
There have been copiers which can selectively implement either the manual copy mode in which the image of an original manually set on the original table is copied or the automatic copy mode in which the images of originals automatically fed by the automatic document feeder are copied. A copier of this kind, as shown in FIG. 1, scans the image of the original set on an original table 138 in the manual copy mode by moving a mirror base 112 of an optical system unit 102 along the undersurface of original table 138 that is disposed on the top of a copier body 100, in the direction in parallel with the print sheet conveying direction inside copier body 100, while in the automatic copy mode it reads the images of originals fed by an automatic document feeder 109 mounted on the top of copier body 100, with mirror base 112 set stationarily at its home position which is detected by a home-position sensor 140.
Specifically, a glass slit 139 is arranged on the top face of copier body 100 at the position corresponding to the home position of mirror base 112. When, in the automatic copy mode, an original is fed within automatic document feeder 109, the image is sequentially read at the portion corresponding to glass slit 139 by optical system unit 102. More detailedly, in the automatic copy mode, mirror base 112 is set stationarily at the home position in copier body 100, then the original set on a document stacker 118 in automatic document feeder 109 is conveyed by the rotations of a pickup roller 113 and a feed roller 114 to a position where the leading edge abuts a resist roller 115. This resist roller 115 starts rotating at a predetermined timing, so that the original is introduced to the position opposing glass slit 139. The original having passed through the position opposing glass slit 139 is then discharged by the rotation of a discharge roller 116 to a document discharge tray 117.
In this way, in the copier in which manual and automatic copy modes can be selectively effected, the scanner unit for reading the image of an original set on the original table in the manual copy mode is also used to read the images of originals fed by automatic document feeder in the automatic copy mode. Therefore, the automatic document feeder is mounted on the top of the copier body where the original table is located, typically in such a manner that it can be opened and closed with respect to the top surface of the original table so as to allow for the manual placement of an original over the original table in the manual copy mode. Further, in order to allow the operator to set an original on and remove it from the original table from the front side of the copier body in the manual copy mode, the automatic document feeder is hinged at the rear side so that it can be opened and closed.
However, in general, in conventional copiers, the document feeding direction in automatic document feeder 109 and the direction of the movement of mirror base 112 of the scanner unit in copier body 100 are configured so as to be perpendicular to the front-to-rear direction of the copier body while, in the automatic copy mode, the scanner unit is configured so as to be set stationarily at the home position at the one side of the moving range. As a result, the essential parts such as pickup roller 113, feed roller 114, etc. in the automatic document feeder are arranged concentratedly on one side with respect to the direction perpendicular to the front-to-rear direction of the copier body. Resultantly, a weight imbalance occurs in the direction perpendicular to the opening and closing direction during opening and closing automatic document feeder 109, making it difficult to smoothly open and close it.
When the original feeding direction of automatic document feeder 109 as well as the direction of the movement of mirror base 112 of the scanner unit inside copier body 100 is configured so as to be along the front to rear direction of copier body 100, the reference position in original table 138 will be laid out on the front side of copier body 100 when the ease of setting originals is considered. Therefore, if a conventional automatic document feeder 109 is used without any modification, the center of gravity of automatic document feeder 109 having heavy load on the reference position side of original table 138 will inevitably reside on the front side of copier body 100 where the opening of automatic document feeder 109 is performed, which degrades the operativity when automatic document feeder 109 is opened and closed.
Further, since reading of the image of an original on original table 138 in the manual copy mode is effected from the home-position side of mirror base 112 in the scanner unit, a stopper is provided for original table 138 on the home-position side of mirror base 112 in order to regulate the position of setting the original to the reference position. Therefore, it is impossible to perform reading the original in the automatic copy mode using this area, so the conventional copier needs to have glass slit 139 which is dedicated to the automatic copy mode, resulting in increase in size and cost of the apparatus.